You will need a 3’ straight edge, a nice sized
drafting triangle, and clamping devices such as straight pins, weights,
etc. You will need a jackplane and a sanding block at least 12” long
that is flat and HARD ... no foam or rubber surfaces to back the paper.
You will also need a straight, flat place to build. It is impossible to
build this wing straight and flat on a crooked table. You may also want to
follow my practice of going to Kinko’s and making a working copy of your
plans, so the originals can be saved and copied again, should the need
arise. You will need slow curing epoxy, fumed silica such as Cabosil,
Titebond aliphatic resin glue, thin CA, and mid-viscosity CA glues. I also
like to keep some 99% isopropyl alcohol handy for cleanup of epoxy.

It’s always best to begin where the most work
is, so I always start with the wings. Please remember that some of these
materials are hazardous, and use caution when cutting carbon, and handling
glues.

Wing:

Cut the plans so that each individual piece of
the model is a separate piece of the plan. For the wing, you may want to
cut the plan into the different panels so they can be built on a different
board. Place either main panel plan on your board and cover with Monokote
backing, or Saran wrap. Don’t use waxed paper for this first step. Find
the spar caps and cut them to length as shown on the plan. Use a Dremel
with a cutoff wheel for this so the cf doesn’t splinter. Taper the
plywood box webs and round the outer corners. Figure out where the shear
webs and the outer ply webs go. Cut the last W-1R rib at he front of the
spar cap notch. (Note that the SW1 webs are 1/4 thick, and that you’ll
have to use 2 of them glued together to make each shear web.) Assemble
this back half of rib with a shear web on both sides. Cut another shear
web in half, and make a full depth, half length web and add it to the
inboard end of this assembly. Note that the assembled spar is very
slightly taller at it’s front edge. A couple of passes over the sanding
block with the shear webs, holding more pressure to the aft edge, will
slightly angle the tops of the webs and angle the top spar cap down at the
back edge.Mix some slow
epoxy and thicken it with cabosil ... NOT microbaloons. Assemble the spar
out to the end of the plywood webs, being careful to make a perfect box of
the spar butt that will house the joiner tube. This assembly will have
only 1 aft W-1R rib section and the spar out to the end of the plywood.
Wrap this assembly with Kevlar tow, making sure the tow stays flat, like a
ribbon, and not round like a rope. Use thin CA only on the plywood webs to
hold it in place, as the top and bottom will be saturated in sheeting the
wing. There should be a hollow area about 5” deep in the root of the
spar. The spar caps and the top and bottom of the plywood outer webs
should be even. The aft plywood web should have made the same passes over
the sanding block to compensate for the airfoil shape. Build both spars
and make sure to make a right and a left. Make sure to use the thicker
spar cap on top.

Starting again, make sure the plan is clear and
covered with waxed paper or whatever you want to keep from gluing the wing
to the plan. Selections for sheeting are important. Use firm sheets for
the inboard panels, and lighter sheeting for the outer panels. Lay out the
bottom wing sheet, including the root section bottom sheet covering to the
trailing edge. Cut, notch, and lay out thetrailing edge, with everything exactly matching the plan. This
should be glued to the center section bottom sheeting, which has been
fitted exactly to the plan, and to the trailing edge. Always pin these
pieces firmly and ensure straightness with the straight edge. Sand a
slight trough in the sheeting area where the Kevlar wrap will lay so the
spar area will remain aligned and the sheeting will not bulge too much
over the spar. Carefully glue the bottom spar cap down to the bottom
leading edge sheet with thick CA, making sure everything lines up exactly
along the aft edge of the spar line. Cut the W-1R ribs fore and aft 1/8”
behind and in front of the spar notches, to clear the plywood webs. Glue
the W 1R ribs to the bottom center sheeting and the spar, using triangle
braces or thickened epoxy to bond the ribs to the spar. If you are
correct, the forward sheet will cover the front rib drawings, and you’ll
be able to see just the faint edge of the back of the spar line on the
plans. You will have a partially assembled spar with the top cap in place
but drooping down as it goes out, and all center section ribs in place. Be
sure to make the 1/8” W-1R rib at the root lean in 3.5 degrees.
Now start with the ribs and shear webs, The shear webs should be an exact
fit, but be ready to correct them if they aren’t. Again, they should be
slightly taller in front, and they should exactly match the rib spar
slots. Generously butter the web and spar with thickened epoxy. Lift the
top cap slightly and slide the web in, followed by the next rib, with a
bit of epoxy on it where it touches the caps and webs. Wipe off the excess
with a good stick, and repeat the process to the end of the wing panel. Be
careful that the ribs exactly match the plan placement. If not, add or
subtract as necessary from the ends of the webs for correct spacing. Note
that the last web space doesn’t get a web, and set the 1/8 joint rib
aside.It is extremely important to have NO gaps between the spar
caps and the webs and ribs. Be sure the leading edges of the ribs are even
and the trailing edge of the ribs are glued back into the trailing edge
notches. Using a piece of scrap trailing edge stock, gently wedge the front of the sheeting up to contact the bottoms of
the ribs. Ca the ribs to the sheet. Remember that anywhere 2 pieces touch,
you will need glue. Thin CA works best for this. Add the 1/4 square
sub-spar using thin CA. Now add the 1/4 sq. leading edge piece. It should
come to the edge of the sheet, but if it doesn’t exactly, it’s OK. Be
sure the leading edge contacts each rib all the way from the top to the
bottom. Also be careful not to push the sheet down off the ribs. If you
are correct, the bottom sheet will be conforming to the ribs up to where
they meet the leading edge, and then will bend down slightly to conform to
the right angle between the ribs and the leading edge. Be sure to CA the
leading edge to the sheeting between the ribs. When this assembly has
cured for a day, it can be lifted from the plan and put out of the way
until ready to join to the outer panel. Build both center panels before
beginning the outer panels, unless you have lots of room and can do both
at the same time.

Build the outer panel by first placing the
notched trailing edge piece and leading edge sheet over the waxed paper
and plan. Again check for straightness. Taper all 4 of the spar caps at
once with a small jackplane. Stack them and do them as 1 piece. They
should taper from 1/8 X 1/2 to 1/8 X 1/4. Block sand as necessary to have
good, clean gluing surfaces. Once tapered, check the fit by laying the
spars out on the plan and slipping the ribs onto it at their positions.
Glue the bottom balsa spar to the bottom sheet with medium CA, using the
straight to ensure straightness. Beginning at W 3, glue the ribs and webs
in place with Titebond, all the way to the end. Check the position of the
front and rear of each rib as you go to ensure straightness and fit into
the trailing edge piece. The end rib of this panel is 1/8 balsa and needs
to tilt 15 degrees, so trim the web accordingly. Apply Titebond to the
tops of the webs and ribs, and press the spruce top spar cap into place.
If you have a clamping arrangement or some way to evenly weight it down,
do that now. Clean off the excess glue that oozes out, to save weight.
Again using the scrap trailing edge, wedge the sheeting up and CA the ribs
to it. Add the leading edge piece just as you did for the center panels.
When dry, about 4 hours, remove from the board and build the other outer
panel. Lay the polyhedral joint ribs aside until ready to join the panels.

Build the winglets in the same way remembering
that where it joins the wing it needs that rib to tilt 15 degrees, so the
winglet can tip up 30 degrees total The only difference is there are no
spars. The sheet should be webbed at the aft edge with 1/32 shear webs.Add the tips and sand them to shape. There is no joiner for this
junction so after the top sheeting is applied and the joint is sanded
straight on the panel and winglet, the winglet is glued on with Titebond
or medium CA.

Plane and sand the leading edges to the proper angle
to allow the sheet to bend over the ribs and smoothly attach to the
leading edge. Remember to use firmer sheets for the inboard panels. Cut
the sheeting to length, allowing a touch extra for curvature in the
joints. Add a strip 3/8” wide to the top sheet for the inboards to give
full coverage from the spoiler bay to the front of the leading edge piece.
Lightly sand the top, front portion of the ribs using 220 grit paper on
your hard sanding block. This should even the tops of the ribs with each
other, and with laser cutting, it should be very minimal. Apply a bead of
Titebond to the length of the front of each rib, stopping 1/8” before
getting to the leading edge or the spar. Apply medium CA to the spar using
a touch extra where the Kevlar wraps the spar. Press the sheeting to the
spar and ribs and hold until the CA grabs. Now apply a bead of medium CA
to the leading edge piece and press the sheet in place, beginning in the
middle and working toward the ends. Be sure the sheet is stuck down to the
leading edge, spar, and all ribs. The sheeting should extend beyond the
spar by 1/4”. This will give some clearance for spoiler linkage. Apply a
few phone books and leave for 2 hours minimum. When dry, add the spoiler
tubes and complete the center section sheeting. Sheet the outer panels the
same way, though the sheeting will not have to have the 3/8 strip added.

When all the sheeting is complete, trim the
polyhedral joint sheeting close enough to sand perfectly straight. Take
your time and make this joint perfect. Prop it up at the prescribed angle
and sand it using the edge of your building board as a guide. Make the
plywood joiners by gluing 8 of the plywood pieces together with epoxy,
with a slight bend in each to match the spar sweep. These will need to
align perfectly with each other, or they won’t fit in the wing. This
piece will need to be fit into each panel carefully by sanding and
trimming. Once satisfied that all pieces fit and the wing panels fit
together correctly at 7 degrees, add the forward sections of the
polyhedral ribs, and epoxy the joiner in place. Epoxy the rest of the
polyhedral joint, with everything propped up and weighted so it is sure
not to move. Be careful to remove the excess epoxy with an alcohol rag.
This cleanup step will make sanding much easier, so don’t omit it. Once
the joint is cured, add the aftribs
and sheet the small section between the sub-spar and the edge of the
d-tube sheeting. Add the radius gusset to the outer panel.

It’s easier to add the tip block and sand it to
shape before the winglet is added, so do that before adding the winglet to
the wing. Sand the winglet joint to fit and either CA it in place or use
Titebond. Make the spoilers from 1/4 X 1 trailing edge stock. Work out
your favorite linkage or make servo platforms as you wish. Do NOT put the
spoiler servo in the leading edge D-tube, as wing strength WILL be
compromised. The wing is ready for sanding at this point. Put it aside
until needed for making the fuselage/wing connection.

Sand the root to it’s 3 1/2 degree angle. Sand the
outside of the 15/32X 12”
brass tubing, and plug both ends with scrap balsa to keep the epoxy out.
The best way to do this is to sharpen the tube edge and use it as a cutter
to cut a plug from scrap 3/32 sheet. Secure these plugs with a drop of
thin CA. DO NOT CUT THE JOINER TUBE! Line up the wings together as if you
were going to make a 1-piece wing. They should fit perfectly together with
both propped up as the plans show. Once this fit is completed, it’s time
to install the joiner tube. Lay one wing flat on the board. Mix a batch of
epoxy and thicken it to the consistency of toothpaste, enough to fill the
cavity around the tube in one wing. Start by filling the cavity about half
full and slowly push the tube in, clearing the epoxy that oozes out. Slip
both of the 1/8” ply root ribs on and glue the first one on to the wing
you’re working with. Slip the tube through the ply rib of the other wing
and slip the wing over the tube. Line the wings up flat and straight, and
allow the epoxy to harden. Fill the cavity of the second wing. Slip this
wing into place, cleaning the epoxy off that oozes out. Glue the rib in
place, and weight the whole thing down straight. If you are correct, your
wings will be flat on the table, perfectly aligned with the root ribs in
place, and about 2” of the tube in the middle. This allows the tubes to
be exactly aligned from one wing to the other. Allow this to cure for a
day, and cut the wings apart by cutting the tube with a zona saw. Add the
alignment pins when the joiner and fuselage are mated. This completes the
assembly of the wing. They are ready for sanding and covering.

Stabilizer:

The stab is built with sticks, is then sanded, and
the leading edge is sheeted with 1/16” sheet. Build both halves at the
same time and saw them apart with a jewelers saw, or zona saw. It’s
easier to keep things aligned by keeping the trailing edge in 1 piece
until sanding is complete. Begin by cutting the 3/16 X 3/4trailing edge stock to size and adding the 1/16 X 1/4 spruce to the
back edge. Pin it down. This will require shimming the aft edge up
3/32”, and the front edge 1/32”. Next add the 1/4 sq. leading edge
piece. Add the tip pieces, and the root pieces, including all gussets and
laying out the tubing. This should have a rough outline of the entire stab
when finished. Add the diagonals. Be absolutely sure to make them fit as
shown, for maximum strength. Use epoxy when installing the tubes, but not
too much. When all glues are hard, lift the stabs and mark the center of
the leading edge down the entire span. Sand them to the shape shown, in
preparation for sheeting. Cut 1/16 X 1/4 spruce for the top and bottom
spar caps. They must be placed where shown on the plan. Glue the bottom
cap to the stab ribs. Apply 1/16 sheet shear webs out 2/3 of the stab
span, and add the top cap. In the tube area, add the shear webs to the
front and back of the caps, filling the voids around the tubes with
thickened epoxy. Sheet the leading edges of the stabs. Add the root area
sheeting and sand to shape. Cut the stabs apart only after all shape
sanding is done. This should leave a nice symmetrical airfoil for the
entire stab.

Rudder:

The rudder is constructed without ribs. It uses
external strips, placing the weight where the strength is needed. Cut the
1/2 sq. fin post and rudder post to length and taper them to 3/8 X 1/2 at
the top as shown. Mark them and drill them for hinge points together. Pin
the rudder post to the plan. Cut the other outline pieces and gussets to
shape and fit them carefully. Use a sanding block to perfect the joints so
there won’t be any gaps in them when you pick it up. Make the trailing
edge by laminating 1/16 sheets with 1/64 plywood in the middle. Use a thin
spread of Titebond for this, and clamp it for an hour. Make sure the ply
protrudes from the front of the laminate 1/4” to index the strip ribs.
Use a piece if 1/16” sheet to shim a piece of 1/8 X 3/8 stick and attach
it to the back edge of the rudder post. It will need to taper as the
rudder does. This will index the strip ribs to the post. Add the laminated
trailing edge to the rest of the framed rudder outline shimmed up 3/16”
to center it with the plywood spline forward. Cut the diagonal strip ribs
to shape and glue them to the rudder post and trailing edge spline and
sheet. When dry, flip the rudder and add the strip ribs to the other side.
Sand the rudder post to a perfect radius to fit slightly into the fin, and
to hinge at the center of the radius. Fit the fin post to the fuselage and
glue the hinge points in place with the hinge line9/32“ behind the post. Glue these only to the fin post at this
time. Slot the rudder post to allow the rudder to swing 30 degrees each
way, while barely missing the fin post. Clamp the assembly into the
fiberglass fin and check for movement. The fin post should be recessed
about 3/16” into the fin. Trim and sand until all the pieces fit and the
rudder swings properly. Put aside until the fuselage is ready.

Fuselage:

The fuselage is a fiberglass Condor fuselage, and you
should have acquired one by now. Mark and drill the joiner holes, index
pinholes, and the holes for the spoiler tubes, or wires, as the case may
be. The stab axle area should be reinforced with 1/16” plywood, and the
axle holes drilled. Use a Dremel with a router attachment for the stab
actuator arc. Once this is done, add the belcrank for the stab, and the
pushrods for the rudder and elevator. The fin post may be added once the
wing and joiner are aligned, and the stab belcrank and pushrods are in
place. I like to use 2 parallel surfaces about 3” apart for aligning
this wing and fuselage. A couple of short 2 X 4s will be fine. Put them on
your workbench, and mark their locations. Mark your joiner so you will
know it’s centered in the fuselage. It has a 7-degree bend in it and
will skew your wings if not properly aligned. Roughen the joiner in the
area inside the fuselage and slip the joiner and incidence pin in place.
Slip the wings on and set the whole assembly on the boards. It’s
important that the boards not move, and are perfectly parallel. Move the
model to be exactly in the middle with the centerline of the fuselage
parallel to the boards. MEASURE...don’t guess.Check that the fin is vertical. Measure from the aft edge of the
polyhedral joint to the fin centerline. It should be the same if the wings
are perpendicular to the fuselage. If not, you will need to adjust some of
the holes in the fuselage. This should be done slowly with a fine round
file, with as little material removed as possible. The bottoms of the
wings should be parallel andthe
wings perpendicular to the fuselage, with the fin perfectly vertical. This
can be frustrating, so take your time, and think about what you’re
doing. You can now tack glue the joiner and incidence pin in place. Use
enough thickened epoxy to be able to remove the wings without disturbing
the locations of the joiner and incidence pins. Let this cure for a day.
Remove the wings and apply thickened epoxy to the entire joiner area to
prevent the joiner from twisting in the fuselage. Place the stabs on their
1/8” music wire joiner. The belcrank will require a piece of 1/8”
brass tubing, just long enough to fit through the fin. This tube will be
bonded into the fin with 1/16 ply backing plates. Locate and drill the
hole for the joiner and rout the arc for the actuator pin. Assemble the
whole model and check the stab for alignment. When viewed from the rear,
the stab should be perpendicular to the fin and level with the wings.
Again, take your time, as these alignment procedures are the most
important steps for a straight flying model. Once this is aligned, glue
the tube to the plywood backing plates with the belcrank and pushrod on
it. Don’t glue the belcrank to anything. It must move freely. Now epoxy
the backing plates into the fin taking care not to get epoxy on any moving
parts. Assemble the model again and make final alignment adjustments to
the stabs. Allow to cure for a day. Remove the wings and stabs and epoxy
the fin post in place, checking with the rudder for movement, and proper
placement. Be careful to keep epoxy off the fuselage exterior...keep it
neat. The fuselage is ready for final assembly.

Final Assembly:

Work out the details for your radio
installation. I like using a 1500 mil nicad pack and 1/8” ply for a
servo tray. Rig your spoilers and ensure operation with thread and masking
tape, or, if you opted for servos in the wings, check the routing of your
cables. Sand the wings carefully. In the area where the spars are wrapped,
the sheeting may bulge slightly. Sand this area to conform to the airfoil,
as the sheeting isn’t too important for strength above the carbon spars.
If you have built it correctly, it won’t get down to the wraps. Sand the
leading edges correctly, using the sanding guides provided with the ribs.
This is the most important portion or the sanding exercise. Once
satisfied, sand the entire wing with 220-grit paper on your hard block.
Work slowly using only the weight of the block for pressure. The wing is
ready to cover. Sand the rudder and stabs as you did the wings. Cover in
your favorite colors of your favorite covering material. Install the
radio, rig the spoilers, and hinge the rudder. Add the tow hook. You are
now ready to balance the model. Because of the sweep of the tips, the
model will balance further back than you might think. Start with the
incidence set at 1 1/2 degrees positive, and 1 1/2 degrees washout from
the poly joint to the tip. Balance the model at 4 1/2 inches behind the
leading edge. This setup will give good performance right off and can be
changed by adjusting the CG and incidence. My suggestion for maximum
performance is to continue to move the CG back, while bringing the
incidence to as close to 0 as possible. I don’t like dive tests much and
I sure don’t recommend inverted flight as a measure of CG accuracy...but
you’ll know when all is right. It will groove in cruise and show
thermals well because it will be pretty easy to upset.